Topic: Gas in the airbox

[bmxjrod]

I've read something on here about this problem but cant find it.... Basically, I have a lot of gas in my airbox, any ideas as too why this is? I just bought this bike, it's the very first motorcycle that I've owned, so I don't know too much about these bikes. Any help would be much appreciated. Thanks!

[MoMo]

If the bike was sitting for a long time, that can happen. Seen it a couple times, remedy is totally disassemble carbs and clean. Also, if someone keeps cranking the bike when it won't start gas will overflow into the carbs. Good luck and welcome...Larry

[Johnie]

Welcome...what bike you got there? Sounds like the floats are sticking and not shutting off the fuel flow in the carb bowls. The overflow tubes can only handle so much fuel and then it gets into the air box. As bmx said a carb cleaning would be good. Depending on what bike you got there you can drop the carb bowls and see if there is junk in the bottom. Plus, check the inside of the tank for crap which could be causing problems too. Any history on the bike as far as maintenance?

[bmxjrod]

Well the guy I bought it from rode it last year, I've rode it twice, and it feels like it's loading up and not running to full potential for about the first 10 minutes. Thats probly due to the air filter bieng full of gas righht???

[MoMo]

A wet air box needs to be changed as it will make the bike run poorly.  You should at least drain the float bowls and see what comes out...Larry

[bmxjrod]

I'll get back at it in the A.M. It's supposed to rain for yet another week, so I may as well tear that apart and get it all cleaned. Whats the best way to the carbs? Tank off, Seat off?

[Johnie]

Again, we need to know what bike you are talking about here...

[MoMo]

On the sohc 4 forum page there is a link to download the manual.

 Johnnie he has a 750-saw it in another post...Larry

[bmxjrod]

Sorry about that... it IS a 750 K6.

[bmxjrod]

Larry, I downloaded that manual last night... I now have it on my desktop, my phone, and my laptop, which is beside my bike in the garage. such a big help right there. thanks man!

[MoMo]

You doing some 24/7 studying?  ...It does seem like carbs need attention, new air filter can be had for way less than the Honda dealer price...Larry

[Tree]

I has an overflowing carb once caused by a needle valve not closing due to sediment from the tank.  I capped the carb bowl drain in order to drive home without leaking gas along the way.  It just caused the gas to back up into the air box and leak from there.  Perhaps you have a blocked drain and stuck needle.

[marty]

I have the same problem, all 4 carbs are leaking into the airbox. I rebuilt the carbs and checked the amount of gas in the float bowls and it's not overflowing. There is no gas leaking out the overflow tubes from the 4 carbs. As far as I can tell, the float bowls fill up to the proper amount of gas, the needle seats properly and cuts off the gas from entering the float bowl but it is re-routed and just flows out the back of the carbs. It doesn't seem to bubble up where the main jet is, it just flows out the brass fitting on the back of all 4 carbs.

Any suggestions how to fix this?

[TwoTired]

Are you certain all the overflow stand pipes and hoses are clear/unblocked?

Anyway, the brass tube at the carb entrance is an air jet which feeds the emulsion tubes.  The fuel level in the carbs should never get this high.

[marty]

I think I've discovered the issue. I pulled the float bowl for carb #2 which I thought might be the culprit. It looks like the float might have been getting hung up on the float bowl. When I closed the float by hand no gas leaked out of any of the carbs. I'm trying to adjust the float so that it won't catch on the float bowl.

I didn't realize it would send gas out of all 4 carbs and into the air box if just one carb is getting too much gas. I also thought that if the float bowl gets too much gas; then it would overflow out of the overflow outlet on the base of the float bowl. Am I mistaken?

[lucky]

Larry, I downloaded that manual last night... I now have it on my desktop, my phone, and my laptop, which is beside my bike in the garage. such a big help right there. thanks man!

When you work on any car or motorcycle or any other machine you need to go buy the workshop manual. End of story.

Not the OWNERS manual, The workshop manual.

[lucky]

I've read something on here about this problem but cant find it.... Basically, I have a lot of gas in my airbox, any ideas as too why this is? I just bought this bike, it's the very first motorcycle that I've owned, so I don't know too much about these bikes. Any help would be much appreciated. Thanks!

If the float bowl vents go into the air box they can suck in a lot of fuel.
There is supposed to be a cover over the ends of the vent tubes to keep fuel from being sucked out of the vent tubes. the cover is not tight on the hoses, but it just separates the airflow or suction.
If the float level is too high then that can also be part of the problem.